csiostor:T5 Firmware fix and cleanup.

This patch fix is to use default firmware configuration files
present in the adapter incase if not available in standard
/lib/firmware/* dir. Additional cleanup is done to reuse flash
related defines from cxgb4 header file.

Please apply over net-next since it depends on previous commit.

Signed-off-by: Praveen Madhavan <praveenm@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>